Two of the National League's best teams from 2012 have been two of its busiest in the winter of '12-'13. That's not just coincidence. The Nationals and Braves separated themselves from the rest of the NL East last season, and now any move that one makes must be viewed in the context of the other club.

The Braves churned even more of their roster than the Nats did, and they likely narrowed the gap between the two teams. But Washington still has the edge as Spring Training approaches, thanks to a starting rotation that remains a good bit ahead of Atlanta's.

It's close, though. And the NL East projects to be quite possibly baseball's most compelling race in 2013, with two legitimate pennant contenders going toe-to-toe for a second straight season.

The gap was narrow in 2012 -- Atlanta's one-game exit in the Wild Card round notwithstanding. The Nationals finished four games ahead of the Braves, which was a pretty fair representation of the actual talent gap.

Washington scored 31 more runs and allowed six fewer, adding up to a four-win gap in the expected won-lost records based on run differential. Baseball Prospectus' third-order winning percentage, which measures team quality based on component statistics and adjusts for schedule strength, also rated the Nats as four games better than the Braves.

In short, Washington was about four wins better than Atlanta in 2012. It's probably a more narrow margin in '13.

The biggest gap between the teams in 2012 was in their starting rotations, where Washington allowed 43 fewer runs -- and health permitting, the Nats have reason to hope for improvement in '13. If nothing else, Stephen Strasburg should be available for more than 159 1/3 innings. They replaced one enigmatic right-hander, Edwin Jackson, with another in Dan Haren.

Jackson posted better results than Haren last season, but Haren was the better pitcher in every previous season. Even in 2012, Haren managed some impressive peripheral stats. If there's a step down, it shouldn't be steep. If there's a worry in the Nats' rotation, it surrounds Gio Gonzalez, whose name appeared in the recent Miami New Times report regarding performance-enhancing drugs. At best, it will be a distraction early in Spring Training for the young lefty.

Atlanta, meanwhile, has lots of upside but less certainty than Washington in its starting five. Kris Medlen was brilliant last year -- so brilliant that it's basically impossible to repeat (though he should make up for that by pitching 60 or so more innings).

The Braves shuffled out the declining Tommy Hanson and the health-hindered Jair Jurrjens and will use a rotation that includes midseason trade acquisition Paul Maholm and homegrown product Brandon Beachy along with Medlen, Tim Hudson and Mike Minor. If there's one area that will make or break the 2013 Braves, it's the rotation. Big years are certainly possible from just about every Atlanta starter, but uncertainty of some sort surrounds nearly all of them as well.

The lineups are … potent. These were the fifth- (Washington) and seventh-highest (Atlanta) scoring teams in the NL last year, though the true difference was probably a bit greater due to the ballparks.

They should both be improved. Bryce Harper ought to take a big step forward in his second year. Denard Span provides a true leadoff man for a Washington team that didn't have one. And though Michael Morse is gone, Tyler Moore might well be just as effective for the Nats given similar opportunity.

Besides, in any kind of just universe, the Nationals can't possibly have the same kind of bad luck with their catchers in 2013 as they did in '12. The string of injuries started to look like the misfortunes that befell Spinal Tap's drummers.

It's harder to swallow improvement in the Braves' offense, but they'll likely have some. Hall of Famer Chipper Jones departs, as do leadoff man Michael Bourn and Swiss Army knife Martin Prado. But Justin Upton is a superstar-caliber player when he's at his best, and a third-base platoon of Juan Francisco and Chris Johnson could be stealthily effective.

The bulk of the Braves' offense is young, though, and that's the main reason to be optimistic. Five of the eight projected primary starters are 25 or younger, an age when improvement is more likely than regression. Even Brian McCann, coming off a frustrating and injury-marred season, is only 28 -- far too soon to write him off.

And then there are the bullpens, the area where Atlanta had the biggest advantage and yet also may have gained the most ground. The Braves bring back virtually their entire relief corps, which was already as good as any in either league. Oh, and they also added Jordan Walden from the Angels.

An impressive Washington 'pen lost a slew of left-handers, and they may well miss them. But it also added Rafael Soriano to an already deep group, and Tyler Clippard might serve as the man to get lefties, despite being right-handed.

They were already two of the best teams in either league. They probably both got better over the past three months. Now we just have to wait to see them go at it. The season can't get here soon enough.